A resistive memory, such as a resistive random access memory, a phase change memory and a magnetic memory, is highly concerned worldwide due to its excellent characteristics in cell area, three-dimensional integration, low power consumption, high erasing and writing speed and multi-value storage and so on.
The array architecture of the resistive random access memory can be divided into passive cross-arrays and active arrays. In the passive cross-array, each memory cell is defined by upper and lower electrodes consisting of intersecting word and bit lines, and the smallest memory cell area—4F2 can be achieved in the planar structure, where F is the feature size. Passive cross-arrays can be stacked in multiple layers due to the independency from the front end of line (FEOL), to achieve a three-dimensional storage architecture. The effective area of each memory cell is only 4F2/N, where N is the number of layers stacked. However, the low-impedance state of the resistive random access memory in the passive cross-array architecture presents an ohmic conduction characteristic. When the resistance of adjacent cross points is read, the crosstalk effect is readily to occur. Taking the 2×2 cross-array shown in FIG. 1 as an example, if three adjacent cross points (1,2), (2,2) and (2,1) are in a low-impedance state, the point (1,1) will have its resistance readout as being a low resistance, regardless of whether the actual resistance thereof is in a high-impedance state or a low-impedance state. When the storage array becomes larger or multi-layer arrays are stacked, the leakage phenomenon will be more serious.
To address the misreading phenomenon caused by the crosstalk, generally a two-terminal device with a non-linear resistance, such as a threshold transition device, a Schottky diode or the like, can be connected in series with the resistance transition device.
However, at present, the two-terminal non-linear resistor generally has a low switching ratio, large leakage current. Further, the threshold transition device must have its transition voltage matched to the operating voltage of the resistive memory. This increases the difficulty in designing the two-terminal non-linear resistor.